is it wise to announce before 12 weeks

So I am currently 8 weeks with baby number 1, and my husband and I were wanting to wait till 12 weeks to announce. However, I decided to tell my bosses early because of my morning sickness, and because I am a teacher and they will need a sub for my maternity leave. I was just trying to make sure I dont screw them over. But now, it turns out that one of them have announced my little secret to a few people. I live in an extremely small town, so if one person is talking, it wont be long before everyone is. And I just dont want my baby to be a rumor going around town. So weve now decided to announce around 10 weeks.

So what I am trying to get at is, have any of you announced early? Is it wise to do this? Im just really upset that our moment was stolen from us, and need some guidance.